[time-nuts] WWVB Response

paul swed paulswedb at gmail.com
Thu Sep 27 14:15:20 UTC 2012


The xtal causes close to zero carrier for a period of time on each phase
shift.
Regards
Paul
WB8TSL

On Thu, Sep 27, 2012 at 10:07 AM, J. Forster <jfor at quikus.com> wrote:

> The AM just makes the situation in low S/N areas worse. The BPSK wipes out
> the possibility of any very narrow band prefiltering, because of filter
> time response.
>
> I suspect, although have not tested, that active antennas with either
> mechanical or crystal filters in their preamps will be rendered useless.
>
> -John
>
> ===============
>
>
> > The AM characteristics have not changed. That means that there is at
> least
> > 10% carrier present at all times.
> > The transmission format seems pretty well documented. The remaining
> > mysteries are in data formatting.
> > Regards,
> > Dale NV8U
> >
> >
> > -----Original Message-----
> > From: Peter Monta
> > Sent: Thursday, September 27, 2012 1:52 AM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] WWVB Response
> >
> > Hi John,
> >
> > Thank you for clarifying the openness of the transmission format.
> > Could I ask whether there is any scenario under which aspects of the
> > signal transmission design might be patented?  If companies or
> > individuals wish to patent aspects of receiver design, that's fine,
> > but I'd be uncomfortable with a patent-encumbered transmission format.
> >
> >> ... It is an unfortunate consequence of improving the reception
> >> capability of our broadcast that this segment of our loyal user base are
> >> so
> >> adversely affected.  The decision to proceed was not taken lightly, but
> >> in
> >> the end it was decided that the improvement in reception capability
> >> (especially along the JJY interference prone East Coast) outweighed the
> >> loss
> >> of use of existing PLL devices.
> >
> > I suppose it's a matter of balancing the value of the PLL receivers
> > and the loss of BPSK signal power to the residual carrier.  If the
> > power loss is small, though, say 0.5 dB or below, then given the large
> > process gains of the advanced receivers, it might be worth
> > considering.  I don't imagine that the mere presence of residual
> > carrier has any effect on the advanced receivers (since it is similar
> > to interference from MSF and JJY, as you say), but please correct me
> > if I'm wrong.
> >
> > Cheers,
> > Peter
> >
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>
>
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